MCP-TY

Instructions

Implementation Reference

• src/mcp_ty/server.py:471-513 (handler)

  The get_completions handler, which is registered as an MCP tool and calls the LSP client to fetch completions.

  async def get_completions(file_path: str, line: int, column: int) -> str:
      """Get code completion suggestions at position (1-based)."""
      client = _get_client()
  
      path = Path(file_path).resolve()
      if not path.exists():
          return _error(f"File not found: {file_path}")
  
      try:
          await client.open_document(path)
          completions = await client.get_completions(path, line - 1, column - 1)
  
          if not completions:
              return _not_found(f"No completions at {path.name}:{line}:{column}")
  
          kind_names = {
              1: "text", 2: "method", 3: "function", 4: "constructor",
              5: "field", 6: "variable", 7: "class", 8: "interface",
              9: "module", 10: "property", 11: "unit", 12: "value",
              13: "enum", 14: "keyword", 15: "snippet", 16: "color",
              17: "file", 18: "reference", 19: "folder", 20: "enum_member",
              21: "constant", 22: "struct", 23: "event", 24: "operator",
              25: "type_parameter"
          }
  
          items = []
          for item in completions[:30]:
              label = item.get("label", "?")
              kind = kind_names.get(item.get("kind", 0), "unknown")
              detail = item.get("detail", "")
              items.append({
                  "label": label,
                  "kind": kind,
                  "detail": detail or None
              })
  
          return _ok({
              "count": len(completions),
              "shown": len(items),
              "completions": items
          })
      except Exception as e:
          return _error(str(e))

• src/mcp_ty/lsp_client.py:630-651 (handler)

  The underlying LSP client method that sends the 'textDocument/completion' request to the ty language server.

  async def get_completions(
      self, file_path: str | Path, line: int, character: int
  ) -> list[dict[str, Any]]:
      """Get completion items at position."""
      file_path = Path(file_path).resolve()
      uri = file_path.as_uri()
  
      result = await self._send_request("textDocument/completion", {
          "textDocument": {"uri": uri},
          "position": {"line": line, "character": character}
      })
  
      if not result:
          return []
  
      # Result can be CompletionItem[] | CompletionList
      if isinstance(result, list):
          return result
      elif isinstance(result, dict) and "items" in result:
          return result["items"]
  
      return []